Copper pentachlorophenate solution



United States Patent O COPPER PENTACHLOROPHENATE SOLUTION Charles ParkesMatzinger, Berkeley, Calif., assignor to The Mountain Copper Company,Ltd., a corporation of Great Britain No Drawing. Application April 28,1958 Serial No. 731,122

4 Claims. (Cl. 167-42) This application is a continuation-in-part of myapplication Serial No. 533,496, filed September 7, 1955, now abandoned.

This invention relates to a method for the preservation of wood andparticularly relates to a novel wood preservative containing copperpentachlorophenate.

Copper pentachlorophenate has heretofore been used as a preservative ofwood, but it has previously been necessary to incorporate copperpentachlorophenate into the wood by means of a complicated technique.Thus, it is first necessary to form a cuprammonium salt of copper andadd this to pentachlorophenol in the presence of a dilute, water solublesolvent to produce an arnmoniacal solution of copper pentachlorophenate.This solution must then be used at an elevated temperature and pressure,so the treatment is complicated and expensive. Further, since thecompound is used with a solvent which evaporates, the copperpentachlorophenate is deposited in solid form and loses its ability tomigrate, and thus does not protect against fresh cuts or holes which maydevelop in the wood.

It is therefore one object of the present invention to provide a stable,non-volatile solution of copper pentachlorophenate which readilypenetrates wood and which may be used with or without pressure.

Another object of the invention is to provide a solvent for copperpentachlorophenate which does not require the use of ammonia.

Still another object of this invention is to provide a formulation ofcopper pentachlorophenate which gives protection to treated wood for anextended period of time and particularly gives potection against freshinjuries to the wood.

A further object of this invention is to provide a pentachlorophenatewhich is easy to store and ship and which can be diluted before use withrelatively inexpensive solvents.

In general, the objects of the present invention are accomplished byutilizing a solvent sold commercially as Lebcol T-40. Lebcol T40 is amixture of the methyl esters of the fatty acids of tallow and is capableof dissolving copper pentachlorophenate; copper pentachlorophenate maybe dissolved in Lebcol T-40 directly, or the process can be speeded upby employing a bridging solvent, such as ethanol or hexylene glycol.

It is possible to incorporate the copper pentachlorophenate into theLebcol T-40 directly. In general, about 5% copper pentachlorophenate maybe incorparted in the Lebcol solution in this manner. However, apreferred solution contains only about 3% copper pentachlorophenate forwhen efiorts are made to incorporate greater quantities somewhatunstable solutions are formed. A temperature of 130-140 C. for a periodof about half an hour is preferably employed as a means of aiding thesolubilization of the copper pentachlorophenate in the Lebcol T-40. Thepurpose of heating to such a temperature is to remove water whereby toproduce a stable solution.

fiililllbll ICC Improved results are obtained by mixing the copperpentachlorophenate with Lebcol T-40 in the presence of a bridgingsolvent such as ethanol or hexylene glycol. Where ethanol is used, atemperature in the neighborhood of -140 C. for one-half hour isnecessary, as above, to drive off the water present in the alcohol.Where hex ylene glycol replaces the alcohol, substantially lowertemperatures are possible, such as set forth in Example 6 below.

Where only Lebcol T40 and hexylene glycol are present, it is possible toplace as much as 40% of the copper pentachlorophenate in solution. This,however, is not ordinarily a stable solution and it is preferred that nomore than about 25% copper pentachlorophenate, as set forth in theexamples, is incorporated in the solution containing the hexylene glycoland Lebcol. Where only Lebcol and ethanol are present, the 5% maximummentioned above applies with 3% being the preferred concentration of thecopper pentachlorophenate in solution.

The preferred method, however, for the preparation of the copperpentachlorophenate solution is by the in situ preparation of the copperpentachlorophenate in the solvent. The copper pentachlorophenate asproduced by the method set forth in my copending patent application,Serial No. 521,629, filed July 12, 1955, is suitable for practicing thepresent invention. In that application, a method is shown of makingcopper pentachlorophenate by reacting pentachlorophenol with copperhydroxide in a solution of ethyl alcohol. This results in the productionof copper pentachlorophenate dissolved in from one to two parts ofalcohol per part of copper pentachlorophenate. The copperpentachlorophenate alcohol solution can then be added to the Lebcol T-40to produce a solution containing as much as about 5% copperpentachlorophenate.

Better results are secured where hexylene glycol is used in place ofethyl alcohol, as set forth in Example 6 below. Far lower temperaturesare possible since there is no necessity for driving oli water and, asindicated above, much larger quantities of the copper pentachlorophenatemay be dissolved. The percentages are as set forth above, a 40% absolutemaximum with 25 being a preferred maximum in solution.

By heating a mixture of Lebcol T-40 and copper pentachlorophenatetogether at a temperature of from 130- C. for about one-half hour, thetwo form a solution either with or without the use of a bridgingsolvent. Further, the heating prevents the subsequent formation of aresidue which sometimes happens where bridging solvent is used withoutheating.

Where more water is present than can be handled readily by the couplingagent, the residue formation seems to take place more readily. Hence,the advantage of heating to drive off water.

The use of ethylene glycol in combination with Lebcol T-40 presents anadditional advantage. When this mixture is used, it is possible to usesubstantial quantities of inexpensive solvents such as the aromatics,paint thinners, and others (but excluding kerosene and the like). Theless volatile extenders are preferred, such as Aromatic Solvent 42,since the wood penetration of copper pentachlorophenate is greater ifthe carrier is present for a longer period of time. Where Lebcol T-40alone or a combination of Lebcol T-40 and ethanol are present withoutthe ethylene glycol, it is found that there is an insufliciently strongcoupling agent present to hold copper pentachlorophenate in solutionshould quantities of paint thinner or stove oil be added. Hence, it ispreferred to use substantial quantities of extenders only where theethylene glycol is used.

The following examples illustrate how solutions may be formed:

Example I.About 3.5 grams of pentachlorophenol in 50 ml. ethanol isadded with agitation to 0.45 gram of copper hydroxide. When solution iscomplete, 50 m1. of Lebcol T-40 is added and the mixture is heated to130 C. for one-half hour. The mixture is then cooled and more LebcolT-40 is added to make a total of 100 grams. The solution contains 3%copper pentachlorophenate and a slight excess of pentachlorophenol. Thisis more concentrated than is necessary for use and can be diluted to a/2% solution either with more Lebcol T-4O or with a solvent such asAromatic Petroleum Solvent 42.

Example 2.A mixture containing 0.45 gram copper hydroxide, 3.5 grams ofpentachlorophenol and 50 ml. of Lebcol T-40 was agitated until all ofthe pentachlorophenol had gone into solution. The mixture was thengradually heated to 130 C. and held at this temperature for one-halfhour. The solution was then diluted with additional Lebcol T-40 to make100 grams and remained stable.

The following examples illustrate the formation of concentratedsolutions of copper pentachlorophenate. In Examples 3-5, the copperpentachlorophenate is made in situ by first mixing the hexylene glycoland Lebcol T-40. The pentachlorophenol and copper hydroxide are thenslowly added with continuous stirring. The solution is warmed slightly(30 C.) and is stirred for 20 to 30 minutes. A stable solution of copperpentachlorophenate is thus produced which can be employed directly inwood preserving, or which can be diluted to the desired concentrationwith additional Lebcol T-40 or with less expensive solvents such asAromatic Petroleum Solvent 42, paint thinner, or the like.

Example 3.To make (by weight) concentration of copperpentachlorophenate:

Formula 45 lbs. hexylene glycol 45 lbs. Lebcol T-40 9 lbs.pentachlorophenol 1.5 lbs. copper hydroxide Example 4.To makeconcentration of copper pentachlorophenol:

Formula 40 lbs. hexylene glycol 40 lbs. Lebcol T-40 18 lbs.pentachlorophenol 3 lbs. copper hydroxide Example 5.To makeconcentration of copper pentachlorophenol:

Formula 37 /2 lbs. hexylene glycol 37 /2 lbs. Lebcol T-40 22 /2 lbs.pentachlorophenol 3% lbs. copper hydroxide In the above examples, thecopper pentachlorophenate was formed in situ in the presence of theLebcol T-40. However, it is also possible to form the copperpentachlorophenate in hexylene glycol and then add the Lebcol T-40, asis shown in the following example.

Example 6.About 45 pounds of hexylene glycol, 9 pounds ofpentachlorophenol and 1.5 pounds of copper hydroxide were stirredtogether at 30 C. for 20 minutes. This solution of copperpentachlorophenate in hexylene glycol was then added to 45 pounds ofLebcol T40 and stirred to produce a solution having the samecharacteristics as that of Example 3.

In the following example, the copper pentachlorophenate was not made insitu, but the solution was prepared from previously made copperpentachlorophenate:

Example 7.-To 20 pounds of copper pentachlorophenate there were addedwith stirring 40 pounds of hexylene glycol and 40 pounds of Lebcol T-40.This produced a solution having the characteristics of Example 4.

The solutions prepared as above may then be used to treat lumber in anydesired manner. Although pressure treatment is entirely feasible withthe solution, it has generally been found that pressure treatment doesnot offer any particular advantage since the composition of the presentinvention readily penetrates the wood upon contact. Further, since thecomposition is not volatile, it is retained by the wood for anindefinite length of time. When the composition of the present inventionis used, it remains a liquid and continued protection is offered asholes or cuts develop in the wood. The wood may be preserved by merelydipping it into the solution, or the solution may be painted onto thesurface of the wood. One attractive alternative is the employment of hotand cold dipping.

One indication of the penetrating powers of the solution of the presentinvention is shown by the fact that 1.4 ml. of a solution prepared as inExample 1 was applied drop-wise to the surface of a fir board. In aperiod of twenty-four hours, the solution traveled completely throughthe board and could be observed on the opposite side.

I claim:

1. As a new composition of matter a mixture of copper pentachlorophenateand the methyl esters of tallow fatty acids.

2. The composition of claim 1 wherein the copper pentachlorophenateconstitutes about 3% of the mixture.

3. The composition of claim 1 wherein ethyl alcohol is present.

4. The composition of claim 1 wherein hexylene glycol is present.

References Cited in the file of this patent UNITED STATES PATENTS UNITEDSTATES PATENT orrrss CERTIFICATE OI CORRECTION Patent No. 2,90l,395August 25, 1959 Charles Parkes Matzin'g er It is hereby certified thaterror appears in the-printed specification of the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 2, lines 56, 6'7, and '72, for "ethylene"', each occurrence, readhexylene Signed and sealed this 12th day of April 19609 (SEAL) Attest:

KARL H AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents

1. AS A NEW COMPOSITION OF MATTER A MIXTURE OF COPPER PENTACHLOROPHENATEAND THE METHYL ESTERS OF TALLOW FATTY ACIDS.